During the operation of a fuel cell system, for generating electric current a fuel cell block formed by stacked fuel cells is conventionally supplied at the anode side with a fuel gas, for example hydrogen, and at the cathode side with air or oxygen. Meanwhile, a large number of different types of fuel cell system exist, which differ in terms of their design, in particular in terms of the electrolyte used, as well as in terms of the required operating temperature.
If ambient air is used as a process gas, it is conventionally supplied via filters in order to rid it of for example dust-containing impurities before it enters the fuel cell block. This is necessary particularly when the fuel cell system is used in an environment where extreme contamination of the air is to be expected. Especially in the case of mobile use of a fuel cell system, for example in the field of shipping for boats or submarines, purification of the process gas is essential in order to guarantee the operating capability of the fuel cell block, particularly given the use of so-called PEM fuel cells.
For supplying the process gases, the use of a liquid ring pump is inferable for example from EP 0 925 614 B1 or EP 0 850 494 B1. The liquid ring pump offers the advantage that, because of the working principle of the liquid ring pump, with compression there is automatically simultaneously a humidification of the process gas.